Load-carrying or lifting devices

ABSTRACT

Apparatus for raising, carrying, or transporting loads, comprises a plurality of expandible elements connected to a base support, and each arranged on expansion to increase the perpendicular displacement between the base support and a load carrying surface of the respective element, and means for creating relative lateral displacement between the base support and the load carrying surface of each element. The expandible elements may be inflatable bags or tubes connected on one side to the base support and resting on the other side on the ground, when inflated, and grouped in parallel rows or sets and inflatable in series so that one bag displaces the adjacent bag laterally and thereby effects displacement of the load.

United States Patent Lewis et a1.

[151 3,693,740 51 Sept. 26, 1972 [54] LOAD-CARRYING OR LIFTING DEVICES Lewis, Quarry House, Seale, Surrey, both of England 22 Filed: Oct. 26, 1970 21 Appl. No.: 83,889

[30] Foreign Application Priority Data 3,537,540 11/1970 Zuppigeretal ..180/8R Baechli ..198/1 X Kyle ..198/220 DD X Primary Examiner-Robert G. Sheridan AttorneyYoung & Thompson [5 7] ABSTRACT Apparatus for raising, carrying, or transporting loads, comprises a plurality of expandible elements connected to a base support, and each arranged on expansion to increase the perpendicular displacement between the base support and a load carrying surface of the respective element, and means for creating relative lateral displacement between the base support and the load carrying surface of each element. The expandible elements may be inflatable bags or tubes connected on one side to the base support and resting on the other side on the ground, when inflated, and grouped in parallel rows or sets and inflatable in series so that one bag displaces the adjacent bag laterally and thereby effects displacement of the load.

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sums 0F 5 llllllllllllllllllllll ITII II II 1| ll of the invention to provide an improved load-handling device which may be capable of raising or carrying loads in difficult situations where conventional loadlifting devices cannot operate, or where the terrain is unsuitable for conventional equipment.

Broadly the invention consists in apparatus for raising, carrying or transporting loads, comprising a plurality of expandible elements connected to a base support, and each arranged on expansion to increase the perpendicular displacement between the base support and a load-carrying surface of the respective element, and means for creating relative lateral displacement between the base support and the load-carrying surface of each element.

According to a preferred feature of the invention the expandible elements themselves constitute the means for providing lateral displacement. For example some of the expandible elements may be arranged to expand both laterally and in a perpendicular direction, so as to create the desired lateral displacement of anadjacent expandible element. In a-convenient construction the expandible elements are positioned at such intervals on the base support that expansion of one element will cause lateral displacement of the same or another element.

The expandible elements may take various forms but are preferably fixed -to the base support and include pivotal or flexible means to provide for the required lateral displacement.

According to another preferred feature of the invention the apparatus includes means for expanding the elements in series, and this control means may be arranged to expand the elements in a series of simultaneouswaves. I I

Conveniently the expandible elements are inflatable bags, tubes, pockets orv the like, formed at least partly of flexible sheet material, and arearranged in parallel rows. Alternatively they may be arranged in orthogonal rows forming in effect a grid pattern of pockets. The apparatus may include a plurality of further like expandibleelements on the opposite side of the'base support and means may be provided for inflating these further expandible elements in series to provide wave forms travelling in the same direction or in the opposite direction as the wave forms produced by the lower elements.

The invention also consists in apparatus as defined connected or connectable to a source of pressure fluid drawings, in which FIGS. 1 a l e are diagrammatic sectional side elevations through one form of load conveyor according to the invention, in a number of sequential positions,

FIG. 2 a. is a sectional side elevation through one of the tubes of such a conveyor, in its natural deflated shape,

FIG. 2 bis an end view of the tube,

FIG. 2 c. is aside view of the tube,

FIG. 3 a is a sectional side elevation through a group of adjacent tubes, joined to-one another along their ad- -jacent wall surfaces,

FIG. 3 b is a sectional sideelevation through another form of tube which may be used in the invention, having locally stiffened side walls,

FIG. 3 c illustrates an alternative to FIG. 3 b with a locally stiffenedand folded lower wall,

FIGS. 4 a 4 f illustrate the sequential positions of :another embodiment of load conveyor device according to the invention,

FIGS. 5 a comprising essentially a series of units designed on somewhat similar lines to the device'of FIG. 4,

FIGS. 6 a and 6 b illustrate a modification of the construction of FIG. 5, 7

FIG. 7 illustrates another embodiment,

FIG. 8 illustrates yet another embodiment with intermediate inflatable pockets between the ground-engaging tubes and the load-carrying surface,

FIG. 9 is a simplified side elevation on a reduced scale of another'form of conveyor according to the invention with two layers of inflatable tubes,

FIG. 10 is a similar side elevation of another embodiment, in which the tubes of the two layers extend in perpendicular directions,

FIG. 11 is a plan view of the embodiment of FIG. 10,

FIG. 12 isia plan view of yet another embodiment, comprising a number of separately inflatable pockets arranged in orthogonal rows, and

FIG. 13 is a diagrammatic illustration of a conveyor according to the invention with inflatable tubes connected in three groups to a portable compressed air generator.

In the embodiment illustrated in FIGS. 1 a e the apparatus comprises a series of parallel inflatable tubes 1,2,3 formed of flexible non-porous material such as rubber, or a fabric coated with a synthetic plastics. The strength of the material and the size of the tubes will depend upon the load to be carried. The tubes are attached at spaced intervals below an overlying sheet or board 10 which may be formed for example of a rigid material such as a light alloy, or a reinforced plastics material, but which is preferably flexible so that when not in use the apparatus can be rolled up for transport or storage. The tubes 1,2,3 extend across the sheet 10 from side to side, at'right angles to the plane of the paper in FIG. I. The individual tubes are each sealed at one end and at the other end are attached to three air supply and discharge manifolds 11,12,13 (see FIG. 13) which conveniently consist of flexible suction/pressure hoses extendingliorizontally at right angles to the inflatable tubes 1,2,3. In each group of three successive inflatable tubes the first, second and third tubes 1,2,3 are connected respectively to the first, second and third manifold hoses 11,12,13. The manifold hoses are provided with releasable couplings for connection to a triple flexible hose 14 leading to a portable compressed air generator 15 which is provided with automatic valve cycling mechanism 16 for admittingair under pressure in succession to each of the three hoses, and venting the remaining two hoses to atmosphere, or applying suction if required. The cycling mechanism is preferably reversible to control the direction of the wave effect which is produced in the series of inflatable 3 illustrate another conveyor device tubes, as described below, and it is also preferably adjustable to control the degree of maximum inflation to suit particular conditions. I

The manner in which the tubes are'inflated to create lateral movement is illustrated in FIGS. 1 a e. As shown in FIG. 1 a the first tube 1 in each group of three is inflated, and the second and third tubes 2,3 are deflated. Each of the tubes is preferably formed in its natural state with an internal fold or re-entrant 18 on its undersurface so that when deflated, as shown clearly in FIG. 2 a the lower wall of each tube tends to rise, so as to-be clear of the ground. As shown in FIG. 1 a the first tubes 1 of each group when inflated lift the upper sheet and thus also raise any load carried by this sheet.

In the next stage in the cycle the second tube 2 in each group of three is inflated as shown in FIG. 1 b During this inflation the second tube expands laterally and downwards and contacts and presses against the adjacent side wall of the first tube thus tending to displace the first tube to the left in FIG. 1 b Since the first tubes are in contact with the ground the overlying sheet 10 is thus moved to the right a small distance. When the second tube 2 in each group of three has been fully inflated the load is shared equally between the first and second tubes, each of the third tubes'3 being collapsed and withdrawn from contact with the ground, and to some extent squeezed between the second tube of one group and the first tube of the next adjacent group as shown in FIG. 1 b In the next stage of the cycle, as illustrated in FIG. 1 c the first tube 1 in each group is deflated so as to withdraw out of contact with the ground, and more or less simultaneously the third tube 3 in each group is inflated, as shown in FIGJI d-. This has an effect somewhat similar to that of FIG. 1 b in that each of the third tubes applies a lateral force to the adjacent second tube moving these second tubes somewhat to the left in the drawing, so that the sheet 10 moves correspondingly to the right in relation to the ground. Wheneach of the third tubes is fully inflated they share the load with the second tubes, and subsequently the second tubes are deflated,'as illustrated in FIG. 1 e while concurrently or shortly afterwards each of the first tubes is again inflated so that the cycle recommences.

In this way a series of waves or ripples are caused in the series of inflatable tubes, as a result of the successive inflation and-deflation of the tubes in each group. The waves progress across the whole undersurface of the device and result in a progressive movement ofthe sheet relative to the ground, while at the same time the sheet is supported about ground level at all times by at least one inflated tube ineach group. It will be noticed that the small lateral movement of the tubes while in contact with the ground is created by the inflation and deflation of the adjacent tubes which expandlaterally and vertically. In order to provide reaction abutments for the two tubes at oppositev ends of the device addi tional inflator tubes 20,21 may be provided at these positions (see FIG. 1 a relatively rigidly secured to the sheet 10, and preferably so arranged that they do not make contact with the ground while the device is in 7 use.

FIG. 2 a illustrates a cross-section through one form of inflator tube 1 in its natural undistorted'state, with an internal fold 18 in its lower wall, reinforced by a doubling'piece 19 whichv is attached when the tube is in the collapsed and folded form shown. Such a tube when inflated under-pressure, assumes an approximately cylindrical shape as seen in FIGS. 2 b and 2 c but when deflated the lower part of the tube wall naturallyrises clear of the ground, so avoiding the risk that it might become trapped 'beneath an adjacent inflated tube. Lugs 20are secured to the upper part of the tube wall to enable it to be attached to the sheet or board 10, and an inflation aperture 21 is provided in one of the conical end walls of the tube. v 7

FIGS. 3 a 3 b and 3 0 illustrate other constructional features which may be of advantage in the invention. In FIG. 3 a the upper parts of the side walls of the adjacent tubes are joined together as shown at 22. This tends to prevent the side walls of any tube from collapsing against each other and this in turn encourages the upward and inward movement of the lower part of the tube wall under suction. In the alternative construction illustrated in FIG. 3 b the whole of the upper and side walls of a tube are stiffened, for example by being given an increased wall thickness, and similarly this encourages the upward and inward movement of the lower wall of the tube when deflated. In FIG. 3 c the lower wall of the tube is locally stiffened to provide an inturned fold 23.

Compressed air will normally be used for inflating the tubes but other gases or fluids may be used if required in special circumstances. For example in some cases a liquid, usually but not necessarily water or oil, may be used.

When the tubes are inflated by a compressed gas it will normally be convenient to control the inflation and deflation by means of automatic cycling valves, but when a liquid is used it may be desirable in some instances to connect each of the three manifolds to a large-capacity hydraulic cylinder whose piston provides the complete volumetric displacement from full inflation to full deflation in a single stroke. Three such pistons can be driven from a single crankshaft with a phase difference of approximately to provide the necessary cycling effect.

It will be understood that the number of tubes in a group can be varied tosuit requirements, and in particular there maybe two, three," four, five, or more tubes in each group. It is also possible when using for example groups of four tubes to arrange that'two out of the four tubes are alternately inflated to carry the load, while the other two, which may be of different sizeand shape, act simply to exert lateral thrusts on the first two load-carrying tubes at the appropriate times, and do not engage the ground. v I

Another possible form of the invention is illustrated in FIGS. 4 a to f The unit illustrated in FIG. 4 a cornprises three separately inflatable tubes 25,26,27, located within a relatively rigid channel 28. This unit is intended to be duplicated at different points along the length of the complete conveyor device, or at least there will be one of these .units at the front and rear ends. The vertical flanges 29,30 of the rigid channel act as abutments for the lateral reaction thrust of the three tubes as they are successively inflated and deflated. In the condition illustratedin FIG. 4 a all three tubes are deflated and assuming that the channel is supported by some other means (e'.g.' by'a similar unit at another position) the tubes would be out of contact with the ground. The sequence of operations in one cycle is illustrated in the remaining figures of FIG. 4. Firstly the left-hand tube is inflated (Figure 4 b so as to push the central tube 26 towards the right-hand end of the channel. Next the central tube 26 is inflated to engage the ground as illustrated in FIG. 4 c The left-hand tube 25 is then deflated (FIG. 4 d and the right-hand tube 27 simultaneously, or immediately afterwards, inflated so that the central tube 26, while still in contact with the ground, ismoved to the left as illustrated in FIG. 4 e This causes a corresponding movement of the channel 28 and of the load-supportingsurface attached thereto, to the right. The central tube 26 is then deflated so as to withdrawupwardsout of contact from the ground as illustrated in FIG. 4 f and subsequently the right-hand tube 27 is deflated. This corresponds to the position of FIG. 4 a so that the cycle can recommence. It will be noted that in this construction only the central tube 26 contacts the ground in operation, and the two adjacent tubes 25,27 act as lateral thrust elements.

The embodiment illustrated in FIGS. 5 a to 5 galso comprises a unit of three inflatable tubes which react against one another, but in this case each tube in turn acts as the load-bearing element. The tubes 30,31,32 are attached to the underside of the load-carrying sheet or board 10 along closely adjacent parallel lines. As seen in FIG. 5 a the tube 30 is just inflated to carry the load. Then, as shown in FIG. 5 b tube 31 is inflated, pushing tube 30 to the left and, consequently, moving the sheet or board 10 tothe rightJTube 30 is now deflated (FIG. 5 c and tube 32 inflated, (FIG. 5 d

causing a further stage of relative movement. Next tube 31 is deflated (FIG. 5 e and tube 30 re-inflated (FIG. 5 f With the deflation of tube 32 (FIG. 5 g the unit returns to the condition of FIG. 5 a

' Units as illustrated in FIG. 5 may be disposed in a continuous array, in which the first tube 30 of each unit is adjacent to the last tube 32 of the preceding unit, or in an interrupted array in which a space is left between each unit. Embodiments of the invention employing such units may in some cases produce a greater movement per inflation cycle than the embodiment of FIG. 1. Using a continuous array, a large ground-engaging surface area is provided, which is useful on soft ground, for example.

In the modified construction shown in FIGS. 6 a and 6 b the outside tubes 301, 321 of each unit have a top portion of their wall secured by adhesive 33 to a reinforcing sheet 34 to which fabric securing lugs 35 are also attached by adhesive. The sheet 34'is attached when the tubes are deflated as shown in FIG. 6 a forming folds of small radius at 341, and 342. The inner side walls of the outer tubes 301, 321 are also attached by adhesive at 331 and 332 to the adjacent side walls of the middle tube 311, the outermost parts of these walls being formed into folds or corners 312, 313, of small radius by the attachment of one or more reinforcing sheets 343, 344. The tubes 301, 311, 321 are thus constrained to fold into the three-peaked form shown in FIG. 6 a when deflated, but can inflate and react against one another much as in the embodiment of FIG. 5.

FIG. 7 illustrates an alternative construction comprising a row of contiguous tubes with common partition walls 35, an upper horizontal wall 36, and inwardly folded bottom walls 37. Such a unit may be formed as a unitary extrusion, with integral end abutment tubes 38. The construction illustrated in FIG. 8 is essentially similar to that of FIG. 7 but includes a series of intermediate tubes or pockets 39 positioned between the lower tubes and the upper load-carrying surface. These pockets 39 may be permanently inflated or otherwise controlled in sequence'to minimize any vertical movements applied to the load during the progressive movement of the conveyor over the ground.

FIG. 9 illustrates a double-sided load conveyor with rows of parallel inflatable tubes 45,46 above and below an intervening horizontal connecting board or sheet 47.

v In this particular example the upper and lower tubes are connected to a common sheet or rigid support 47, but it is also possible to use two separate load-carrying mats" similar to that illustrated in FIG. 1, simply arranged back-to-back. With such devices it is convenient to provide independent control of the inflation and deflation of the tubes in the upper and lower levels. For example if the upper and lower tubes are succes sively inflated and deflated to provide a wave motion or ripple effect moving in the same directions across the upper and lower surfaces, such a device will tend to insert or insinuate itself between an article and the ground, or between two articles,or to remove itself from beneath an article. After having inserted itself beneath anarticle it is then possible to transport the article by interrupting the sequential inflation of the upper tubes and continuing the wave-like inflation of the lower tubes. Alternatively in some situations the action can be reversed with the sequential inflation applied to the upper tubes, and the lower tubes de-energized, so that the matremains stationary on the ground and any loads supported on the upper tubes are progressively discharged to one side. Likewise for some operations it may be of advantage to create wave forms moving inopposite directions in the upper and lower tubes.

FIGS. 10 and 11 illustrate a modification of the double-layer construction of FIG. 9, where the two'layers extend horizontally at right angles to one another. Such a construction may be useful in some situations in order to provide controlled movement in two directions at right angles.

FIG. 12 illustrates another possible modification in which the device comprises a multiplicity of rectangular pockets arranged in an orthogonal matrix. Means are provided for selectively inflating the pockets individually, to provide wave motion in either, of the two perpendicular directions in which the rows of pockets extend. With such a device it is possible to transport a load and to guide it at will in confined spaces between other objects, or around bends.

FIG. 13 is a diagrammatic plan view of a conveyor mat, similar to that illustrated in FIG. 1 connected to a portable compressor/suction pump through an automatic cycling valve.

It will be understood that the inflatable elements may take a variety of different shapes other than tubular, for example they may be spherical or part-spherical or of complex curvature. In some applications it may be convenient to form a whole series of the inflatable elements as a common extrusion in a flexible material. In

7 another possible construction each of the inflatable elements is of bellows-type construction. In any case the spacing between the elements is preferably such that they provide lateral thrust reaction between each other as they expand and contract, in order to develop the required lateral progressive movement. Since the device can be constructed in lightweight materials, and since in use a considerable number of the inflatable elements will'normally be inflated, the device will have considerable buoyancy and can therefore be used in some applications to provide a degree of floatation or to prevent a load sinking into waterlogged ground. The device can also be combined in use with. otherconventional forms of load transporters, such as pallets, trolleys, pneumatic lifting bags, fork-lift trucks, or the like, and in some applications will be used inverted, i.e. with the load-carrying surface on the ground, or on some other supporting body.

The inflation can also be applied to conveyor mats which are of special non-planar shape to suit particular applications, e.g. for supporting loads of unusual shapes and for moving on non-planar surfaces. For example the inflatable tubes may be curved in directions transverse to the direction of movement, or of noncylindrical shape to fit into trough-shaped supports, for example to convey barrel-shaped objects, or loads such as boat hulls. The tubes may have concave profiles for such purposes, or convex profiles if used to enter, and possibly plug, a hollow cylindrical body such as a pipe. if of annular construction the tubes can be used to convey articles through a hollow pipe, or to move a pipe along an internal supporting bar.

We claim,

1. Apparatus for raising, carrying or transporting loads, comprising at least three inflatable elements arranged in lateral co-operating relationship and expandible at least laterally upon inflation, non-expandible means interconnecting adjacent elements at points offset from the resultant of lateral force exerted by the elements on each other when inflated, and means for sequentially controlling inflation and deflation of said elements to cause lateral movement of parts of said elements with respect to the interconnecting means.

2. Apparatus according to claim 1, in which at least some of the inflatable elements are also expandible vertically upon inflation. I

3. Apparatus according to claim 1, in which a rigid base provides said interconnecting means, said inflatable element being on one side thereof.

4. Apparatus according to claim 3, including a plurality of further like inflatable elements on the opposite side of said base, and means for sequentially controlling inflation and deflation of these further elements.

5. Apparatus according to claim 1, wherein the sequential controlmeans is adapted to expand the elements in a series of waves of a length equivalent to at least three adjacent elements.

6. Apparatus according to claim 1, in which the inflatable elements are arranged in parallel rows.

7. Apparatus according to claim 1, in which the inflatable elements are arranged in orthogonal rows.

8. Apparatus according to claim 1, in which the inflatable elements are tubes of flexible material arranged to collapse when deflated with an internal fold in such a manner that their lower walls are raised clear of the ground.

9. Apparatus according to claim 8, in which reinforcing or doubling sheets are attached to the tubes to constrain them to assume the internal folded form or deflation. 

1. Apparatus for raising, carrying or transporting loads, comprising at least three inflatable elements arranged in lateral co-operating relationship and expandible at least laterally upon inflation, non-expandible means interconnecting adJacent elements at points offset from the resultant of lateral force exerted by the elements on each other when inflated, and means for sequentially controlling inflation and deflation of said elements to cause lateral movement of parts of said elements with respect to the interconnecting means.
 2. Apparatus according to claim 1, in which at least some of the inflatable elements are also expandible vertically upon inflation.
 3. Apparatus according to claim 1, in which a rigid base provides said interconnecting means, said inflatable element being on one side thereof.
 4. Apparatus according to claim 3, including a plurality of further like inflatable elements on the opposite side of said base, and means for sequentially controlling inflation and deflation of these further elements.
 5. Apparatus according to claim 1, wherein the sequential control means is adapted to expand the elements in a series of ''''waves'''' of a length equivalent to at least three adjacent elements.
 6. Apparatus according to claim 1, in which the inflatable elements are arranged in parallel rows.
 7. Apparatus according to claim 1, in which the inflatable elements are arranged in orthogonal rows.
 8. Apparatus according to claim 1, in which the inflatable elements are tubes of flexible material arranged to collapse when deflated with an internal fold in such a manner that their lower walls are raised clear of the ground.
 9. Apparatus according to claim 8, in which reinforcing or doubling sheets are attached to the tubes to constrain them to assume the internal folded form or deflation. 